Grafting materials, such as autologous bone, allograft bone, xenograft, organic or inorganic material or "bone paste", or other similar materials, are commonly used in procedures for fractures or surgical reconstruction of bones. These materials are used for two primary reasons--(1) in order to promote bone healing as a biologic response, and (2) in order to provide structural support.
Intraarticular fractures are a common example of a situation in which grafting material can be used. In this situation, the primary role of the grafting material is to buttress and/or support bone fragments in an anatomic or functional position; in addition, the graft material may function to promote healing.
If the grafting material does not maintain its position at the site of application, several potential problems may occur. First and foremost is that the material no longer functions for its original and intended purpose. Migration of graft material may lead to migration of the fragment to be supported; this in turn may result in complications of joint incongruity, arthritis, stiffness, pain, crepitance with joint motion, non-union or malunion, and secondary procedures (i.e. additional surgical procedures), to name a few.
In addition to losing intended function, migration of graft material may have additional deleterious effects. Migration of grafting material into adjacent soft tissues may initiate an inflammatory reaction or cause complications from mechanical pressure and irritation. For instance, graft material pressing on a nerve may cause nerve damage. Graft material pressing on tendons may cause either fraying of the tendon (even rupture) or may cause scarring and limitation of tendon gliding. Migration of graft material into an adjacent joint can cause arthritis and joint damage. Moreover, the ability of grafting material to stimulate bone formation may cause problems if the graft migrates into the soft tissues. Occasionally, this may even stimulate formation of heterotopic bone in the soft tissues, which can cause scarring, stiffness, inflammation and pain.